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Rotax 503: Need Expert Experience & Wisdom

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Victor Bravo

Well-Known Member
Supporting Member
Joined
Jul 30, 2014
Messages
13,447
Location
KWHP, Los Angeles CA, USA
HHEEELPP !!!!

I have an opportunity to buy a certain type of aircraft that I am fond of. Three of the four advertised on Barnstormers are equipped with Rotax 503 engines.

My long-term plan is to install a 4 stroke engine, but one of these aircraft is close enough to fly back home. Even if I shipped another one of them back here, I also would not mind flying a little bit with the original engine, so I can make a reasonable comparison between the 503 and whatever 4 stroke engine I eventually install (O-100, HKS, etc.).

If I'm going to be flying a 2 stroke engine in this uniqe environment where I live....

https://upload.wikimedia.org/wikipedia/commons/d/d7/Los_Angeles,_CA_from_the_air.jpg

... even for one hour, I want to be sure that I am doing everything as safely as possible. I have ZERO experience flying behind a 2 stroke. I DO NOT want to be the guy on the TV news standing in the mobile home park next to the wreckage.

Here is everything I know or have heard about the 503 engine:

- One of the best engines Rotax ever made.
- Bullet-proof reliable.
- Piece of junk, it'll kill you dead, buy a Hirth instead.
- Makes a really good artificial reef for a large aquarium.
- It is not a question of if a Rotax 2 stroke is going to fail, but when.
- The 503 burns fuel faster than a big-block V-8
- Run it WIDE OPEN ALL THE TIME and it will never get all carbon'ed up and fail.
- Baby the engine, REDUCE POWER as soon as you climb out from takeoff.
- Use Amsoil.
- Use Marvel Mystery Oil.
- Use Pennzoil.
- The high temp ceramic coatings make a huge positive difference.
- Don't waste your money on coatings.
- The Rotax maintenance plan says you have to overhaul it at 300 hours.
- The Rotax maintenance plan was written by the parts sales department, run it 500 hours.
- They seize in hot weather.
- They seize in cold weather.
- If you know how to run them, they're very reliable.
- Every so-called "expert who knows that they're doing" has had 10 engine failures.
- They sound like a vacuum cleaner married a chainsaw.
- The intake silencer costs you 10 horsepower.
- The gearbox and propeller makes more noise than the motor.
- The C gearbox has an idle speed clutch that reduces 90% of the wear and damage from the rough idle.
- Celebrity Rotax Expert #1 knows everything, walks on water, do what he says, everyone else is stupid.
- Celebrity Rotax Expert #2 is a genius, the other guy is stupid, his followers are a brain-dead cult.
- Don't trust Celebrity Rotax Experts who sell you unofficial parts and tell you 'everything is fine, just add more oil!'.
- MY crankshaft seals are better than THEIR crankshaft seals.
- THEIR crankshaft seals are made of Yeti blubber and MINE are Sasquatch intestine.
- I've been doing this for 15 years, I'm an expert!
- I've been doing this since he was in Kindergarten!
- I invented the internal combustion engine.

Other factoids:
One or two of the engines on the airplanes I might buy have the oil injection system. A couple do not.
One or two have electric starters, one or two have pull starters.
One of the engines has 220 hours on it, and the official Rotax manual says it has to be overhauled in 80 hours.
Every single one of the sellers says "It runs GREAT!!! Never had any problems !"
I do not want to discuss the airworthiness certificate and associated limitations. Have a DAR and retired FAA ppwk inspector on call.
I already know that 4 strokes are a better long-term choice than 2 strokes.
I have greater-than-average experience with off-airport emergency landings.
I have the ability to make whatever arrangements with ATC that need to be made.
Got a private pilot license.
The airplanes I am looking at all have N numbers
Already planning the safest possible route through the airspace around my home airport.


So, what I need from this group is to understand what the REALITY is, and what I need to do (on the ferry flight home or during the time I fly it here over the city). I need to know which of the old wives' tales are true, which urban legends and old stories are false, and I need to know each and every stupid bonehead mistake that an inexperienced Rotax 503 owner makes.

Thank you all in advance for experience and wisdom on the 503 that I do not have.
 
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